Abstract: Objective To study the effects and its mechanism of Que on the chemotherapeu-tics sensitivity of human breast cancer cells. Methods The effect of Que on the growth of human breast cancer MCF-7 cells was examined by MTT assay.MCF-7 cells were treated by ADR with or without non-cytotoxic dose of Que.Then，the proliferative capacity of the cells was measured using MTT assay，the cell cycle was analysed using flow cytometry，the invasive capacity was measured by transwell chamber invasive model，HIF-1α mRNA level was determined by RT-PCR，and HIF-1α protein expression was detected by Western b1ot assay. Results Less than 0.7 μM Que had non-cytotoxic effect on the growth MCF-7 cells.Compared with ADR alone action on MCF-7 cells，0.7 μM Que could enhance inhibitory rate of cell growth，more apoptotic cells，inhibitory capability，and expression of HIF-1α mRNA and protein with the same dose of ADR. Conclusion Que has potential application in the treatment of chemotherapy-resistantbreast cancer.